America's historic identity as a people with a universal mission faces a new era in Obama's nomination of Chuck Hagel as defense secretary. Israel and even military cuts aren't the core issues. America's 'special role' is.

Americans may want to follow the Senate debate over the nomination of former Sen. Chuck Hagel, a Republican, to be secretary of Defense. The debate is really about them.

The decorated war veteran, if confirmed, would be in charge of making deep cuts to military spending, such as possibly reducing Army troops by at least 14 percent. Yet unlike previous Pentagon downsizings, such as after World War II and Vietnam, these cuts won’t be driven only by budget necessities or an attempt to readjust America’s special role in the world to new circumstances. They might also be a downsizing of the very idea that the United States even has a special role.

A Hagel Pentagon would be a concrete step by Mr. Obama to fully redefine American “exceptionalism” – a term he once mocked – toward the notion that the US cannot easily rely on force to defend the global order or to advance universal values.

If the US has a historic global mission left from its Puritan origins or the ideals of the American Revolution, the president wants it to be one of restoring the nation’s strength at home and resetting its own moral order. He wants to make the US a just society far more than adjusting others. He wants it to be only one of many nations in any foreign adventure.

Refitting the military toward mainly a US-centric defense posture would be a shift from a century-long American role that stretched over three world wars – World Wars I and II and the cold war – and then through smaller conflicts from the 1991 Gulf War to the remote US bombing of Libya in 2011. Most of those wars were to defend or promote liberty, with a big exception being the post-9/11 ouster of Al Qaeda from Afghanistan.

Obama is hardly out of step with Americans. In past decades, the portion of people who support the US advancing democracy abroad has fallen, with a sharp decline since 2001 from 29 percent to 13 percent, although Americans do support the use of diplomacy, investment, and other “soft power” tools.

A Hagel Pentagon might be a far cry from Thomas Jefferson’s vision of America as an “empire of liberty” or the current vision by many strategists of the US as indispensable to global stability. It could alter America’s identity from that of having a mission to the world based on its founding values to that of being miserly in its foreign commitments.

An early Puritan minister, Peter Buckley, helped set America’s identity by telling the Christians of New England that “the Lord looks for more from thee, than any other people.” That sense of mission continued into the 19th century when Alexis de Tocqueville wrote, “The position of the Americans is therefore quite exceptional, and it may be believed that no democratic people will ever be placed in a similar one.” But the nomination of Hagel could reflect a new America, one far more uncertain of engaging overseas.

He once told a West Point class that the US should send soldiers into combat only for “a mission that matters.” For the sake of Americans being clear on their role in the world, he should tell senators what kind of missions he would support. It would be critical if Obama is to define America’s special role.